docs: def get_docs_sources_from_ES(self):
          """Get document sources using MGET elasticsearch API"""
          docs = [doc for doc, _, _, get_from_ES in self.doc_to_update if get_from_ES]
          if docs:
              documents = self.docman.elastic.mget(body={"docs": docs}, realtime=True)
              return iter(documents["docs"])
          else:
              return iter([])